吸附溶出伏安法测定痕量砷的研究

Determination of Trace Amouts of Arsenic by Adsorptive Stripping Voltammetry

在稀盐酸底液中,砷(Ⅲ)与吡咯烷二硫代甲酸铵(APDC)形成的络合物在悬汞电极(HME)上有良好的吸附溶出行为,于—0.53V(vs. SCE. )处有一灵敏的二次导数溶出峰。在1.3×10^(-9)—2.6X10^(-7)mol/As(Ⅲ)浓度范围内,峰高与As(Ⅲ)浓度有良好的线性关系,检出限为1.3×10^(-10)~mol/L。曾用本法测定两种标样以及茶叶中的砷,结果满意。本文还研究了电流性质及电极过程机理。

The adsorptive stripping behaviour of the complex formed by As ( Ⅱ ) with ammonium pyrrolidine dithiocarbamate (APDC) on HME has been studied. In 0. 5mol/L HC1 solution , As (Ⅱ ) -APDC complex gives a sensitive secondary differential adsorptive cathodic stripping peak at -0. 53V (vs. SCE). A simple, sensitive and selective adsorptive stripping voltammetric method has been established for the determination of trace arsenic. There is good linear relationship between the peak height of i', and concentration of As ( Ⅱ ) in the range of 1. 3× 10-9-2. 6× 10-7mol/L ,and the detection limit is 1. 3× 10-10mol/L. The result for the determination of trace, arsenic in several biological materials (standard sample and tea ) is very satisfied. The mechanism of electrode process and current property has also been discussed.